Some rotorcrafts include cowling assemblies configured to act as a protective fairing around the engine and other propulsion related components. Certain rotorcraft configurations can include an engine housed in a nacelle which acts as an aerodynamic pod for the engine. The nacelle configuration can be implemented when the engine is located at a distance from the fuselage, such as on a wing of the rotorcraft. Inlet systems can be used to provide an aerodynamic flow path from the exterior of the cowl door assembly (or nacelle) to the engine inlet. In some configurations, filtration systems can be installed in the inlet systems.